This invention relates generally to the treatment of incontinence. More particularly, the instant invention is related to artificial sphincter systems and associated method for returning volitional control of excretory vessels to the patient.
Sphincter muscles are utilized by the body to close various duct tubes or orifices. The sphincter muscle encircles or surrounds its associated duct tube so that contraction of the sphincter will constrict the passageway. Urethral sphincter muscles, for example, preferably volitionally open and close the urethra during micturition. Where sphincter muscles or their associated nerves and fibers become inoperative because of disease or damage the unfortunate problem of incontinence will result. A plurality of prior art artificial mechanisms have been developed in an attempt to solve the problem of incontinence. Most of these devices function by intermittently occluding the affected vessel.
Artificial sphincter mechanisms for exteriorly controlling incontinence are shown in U.S. Pat. No's. 2,455,859 and 2,533,924 issued to F. E. Foley on Dec. 7, 1948 and Dec. 12, 1950, respectively. The latter two references are directed towards apparatus for controlling incontinence in males by exteriorly clamping the urethra. As described in the latter two patents, the exteriorly operable Cunningham clamp represents a now-outdated approach for controlling incontinence.
Surgically implantable devices for controlling incontinence are shown generally in U.S. Pat. No. 3,750,194 issued to G. D. Summers on Aug. 7, 1973, U.S. Pat. No. 3,744,063 issued to McWhorter et al on July 10, 1973 and U.S. Pat. No. 3,863,622 issued to R. E. Buuck on Feb. 4, 1975. The latter patents generally disclose apparatus comprising a circular cuff member responsive to fluid pressure for intermittently occluding a vessel, at least one source of fluid pressure interconnected to the cuff, and one or more interconnected valves, tubes, reservoirs or the like. An informative article related to the latter art and entilted "Intermittent Occlusion System" was published in IEEE Transactions on Bio-Medical Engineering, October 1970, Volume 17, No. 4, page 352. U.S. Pat. No. 3,538,917 issued to R. G. Selker on Nov. 10, 1970, illustrates an occlusion clip for selectively blocking flow through a vessel which includes an expandable, pressure-responsive member which proximally circumscribes the indicated vessel. U.S. Pat. No. 3,853,122 shows a delay means.
While the aforementioned implantable devices represent a significant improvement over earlier external clamping techniques, they are not without certain disadvantages. Prior art implantable sphincters may become disengaged in repsonse to bladder spasms or other external forces which tend to force pressurizing fluid out of the vessel-constricting cuff. In a urethral incontinence system for example, reduced cuff pressure may result in involuntary passage of urine. Another problem associated with certain prior art implantable sphincter systems is that the cuff inflation means utilized therewith may produce excessive pressure conditions which can lead to tissue damage. For example, where a prior art inflatable sphincter member has been implanted tissue damage may result unless fluid can be at least temporarily displaced from the cuff member in response to vacillating external forces on the urethra. Known prior art sphincters must be volitionally manipulated each time the affected vessel is to be either opened or closed